PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.

• Rhodococcus equi mice virulence cyclophosphamide

Abstract in Portuguese:

ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.

Abstract in English:

Vargas A.C., Costa M.M., Groff A.C.M., Viana L.R., Krewer C.C., Spricigo D.A. & Kirinus J.K. 2005. [Antimicrobial susceptibility of Campylobacter fetus subsp. venerealis isolated from cattle.] Susceptibilidade antimicrobiana de Campylobacter fetus subsp. venerealis isolado de bovinos. Pesquisa Veterinária Brasileira 25(1):1-3. Laboratório de Bacteriologia do Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. E-mail: agueda@ccr.ufsm.br Venereal campylobacteriosis is associated with infection of Campylobacter fetus subsp. fetus and Campylobacter fetus subsp. venerealis. The etiological agent is transmitted by natural bull breeding or artificial insemination using contaminated semen. The present study aimed to determine the in vitro susceptibility of C. fetus subsp. venerealis isolates to antimicrobial drugs generally used in clinical and semen treatment. Reference strains of C. fetus subsp. fetus and C. fetus subsp. venerealis and 21 C. fetus isolates were tested. The susceptibility test was performed by using the modified Kirby-Bauer diffusion disc method. C. fetus subsp. fetus reference strain was resistant to lincomycin and penicillin. C. fetus subsp. venerealis was susceptible to all antimicrobial tested, with exception to C.C. KrewerDnalidixic acid. C. fetus subsp. venerealis samples were sensible to amikacin, ampicillin, cefalotin, streptomycin, gentamycin, penicillin and tetracycline. Drug resistance was observed on 42.86% of lincomycin, 4,76 % of enrofloxacin, and 100% to nalidixic acid. In addition 4.76% of the isolates showed intermediate susceptibility to enrofloxacin, neomycin, polimixin B and 9.52% to lincomycin. The susceptibility of C. fetus isolates to antimicrobial drugs commonly used in clinical and semen treatment was demonstrated.

• Campylobacteriosis cattle semen antibiomicrobials.

Abstract in Portuguese:

Vargas A.C., Costa M.M., Groff A.C.M., Viana L.R., Krewer C.C., Spricigo D.A. & Kirinus J.K. 2005. [Antimicrobial susceptibility of Campylobacter fetus subsp. venerealis isolated from cattle.] Susceptibilidade antimicrobiana de Campylobacter fetus subsp. venerealis isolado de bovinos. Pesquisa Veterinária Brasileira 25(1):1-3. Laboratório de Bacteriologia do Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. E-mail: agueda@ccr.ufsm.br Venereal campylobacteriosis is associated with infection of Campylobacter fetus subsp. fetus and Campylobacter fetus subsp. venerealis. The etiological agent is transmitted by natural bull breeding or artificial insemination using contaminated semen. The present study aimed to determine the in vitro susceptibility of C. fetus subsp. venerealis isolates to antimicrobial drugs generally used in clinical and semen treatment. Reference strains of C. fetus subsp. fetus and C. fetus subsp. venerealis and 21 C. fetus isolates were tested. The susceptibility test was performed by using the modified Kirby-Bauer diffusion disc method. C. fetus subsp. fetus reference strain was resistant to lincomycin and penicillin. C. fetus subsp. venerealis was susceptible to all antimicrobial tested, with exception to C.C. KrewerDnalidixic acid. C. fetus subsp. venerealis samples were sensible to amikacin, ampicillin, cefalotin, streptomycin, gentamycin, penicillin and tetracycline. Drug resistance was observed on 42.86% of lincomycin, 4,76 % of enrofloxacin, and 100% to nalidixic acid. In addition 4.76% of the isolates showed intermediate susceptibility to enrofloxacin, neomycin, polimixin B and 9.52% to lincomycin. The susceptibility of C. fetus isolates to antimicrobial drugs commonly used in clinical and semen treatment was demonstrated.

Abstract in English:

ABSTRACT.- Brum M.C.S., Weiblen R., Flores E.F, Tobias F.L., Pituco E.M. & Winkelmann E.R. 2002. [Fetal protection against challenge with bovine viral diarrhea vírus (BVDV) in pregnant ewes immunized with two strains experimentally attenuated.] Proteção fetal frente a desafio com o vírus da Diarréia Viral Bovina (BVDV) em ovelhas prenhes imunizadas com duas amostras de vírus atenuadas experimentalmente. Pesquisa Veterinária Brasileira 22(2):64-72. Depto Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria (DMVP/CCR/UFSM), Santa Maria, RS 97105-900, Brazil. E-mail: flores@ccr.ufsm.br Two isolates of bovine viral diarrhea virus (BVDV) submitted to multiple passages in tissue culture associated with ultraviolet irradiation were evaluated as vaccine virus candidates. The attenuation of the modified viruses was assessed in calves and in pregnant ewes. Intramuscular inoculation of the viruses in four seronegative calves produced only a mil d and transient rise in body temperature, followed by the production of high titers of neutralizing antibodies. The viruses were not detected in nasal secretions or in the blood following inoculation. However, intramuscular inoculation of these viruses in four pregnant ewes resulted in transplacental transmission and infection of ali fetuses. To assess fetal protection conferred by immunization, pregnant ewes immunized twice with the modified viruses were subsequently challenged by intranasal inoculation of BVDV-1 (SV-126.8, n=6) or BVDV-2 (SV-260, n=5). At the day of challenge (134 days after the second immunization), ali ewes had high titers of neutralizing antibodies (256 to >4096) to the vaccine viruses and variable titers (8 to >4096) to Brazilian BVDV-1 and BVDV-2 field isolates. Fifteen days after challenge, the ewes were euthanized and fetal tissues were examined for infectivity. Ali fetuses from non-vaccinated, challenged ewes (n=4) were infected. In contrast, none of the fetuses from the immunized dams (n = 11) were positive for virus, indicating that the immunological response induced by immunization with the vaccine candidate viruses was capable of preventing fetal infection. These results indicate that it is possible to achieve fetal protection to BVDV by induction of a strong immunological response using modified live vaccines.

• Bovine viral diarrhea virus BVDV vaccine fetal protection sheep Vírus da Diarréia Viral Bovina vacina proteção fetal ovelhas.

Abstract in Portuguese:

RESUMO.- Brum M.C.S., Weiblen R., Flores E.F, Tobias F.L., Pituco E.M. & Winkelmann E.R. 2002. [Fetal protection against challenge with bovine viral diarrhea vírus (BVDV) in pregnant ewes immunized with two strains experimentally attenuated.] Proteção fetal frente a desafio com o vírus da Diarréia Viral Bovina (BVDV) em ovelhas prenhes imunizadas com duas amostras de vírus atenuadas experimentalmente. Pesquisa Veterinária Brasileira 22(2):64-72. Depto Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria (DMVP/CCR/UFSM), Santa Maria, RS 97105-900, Brazil. E-mail: flores@ccr.ufsm.br Duas amostras do vírus da Diarréia Viral Bovina (BVDV) submetidas a múltiplas passagens em cultivo celular e exposição à radiação ultravioleta (UV) a cada passagem foram avaliadas como candidatos a vírus vacinais. As amostras foram testadas quanto à sua atenuação para bezerros e fetos ovinos, reatividade antigênica contra isolados de campo, e capacidade de induzir proteção fetal em ovelhas prenhes. Inoculação intramuscular (IM) dos vírus modificados em quatro bezerros produziu apenas uma elevação discreta e passageira da temperatura corporal, seguida de produção de altos títulos de anticorpos neutralizantes. O vírus não foi detectado em secreções nasais ou sangue nos dias seguintes à inoculação. Porém, a inoculação IM desses vírus em quatro ovelhas prenhes foi seguida de transmissão transplacentária e infecção em todos os fetos. Para os testes de proteção fetal, ovelhas prenhes previamente imunizadas com duas doses vacinais, foram inoculadas por via intranasal com amostras de BVDV-1 (SV-126.8, n=6) ou BVDV-2 (SV-260, n=5). No dia do desafio (134 dias após a segunda dose), todos os animais apresentavam altos títulos de anticorpos neutralizantes (256 a >4096) contra os vírus vacinais; além de títulos variados (8 a >4096) contra várias isolados brasileiros de BVDV-1 e BVDV-2. Quinze dias após o desafio, as ovelhas foram sacrificadas e os tecidos fetais foram examinados para a presença de vírus. Todos os fetos das ovelhas controle não-vacinadas apresentaram-se (n=4) positivos para os vírus utilizados no desafio. Em contraste, nenhum feto das ovelhas imunizadas (n = 11) foi positivo para vírus, indicando que a resposta imunológica induzida pela vacinação com os vírus modificados foi capaz de prevenir a infecção fetal. Estes resultados indicam que é possível obter-se forte resposta imunológica e proteção fetal contra o BVDV com o uso de vacinas vivas modificadas.

Abstract in English:

Grazing behaviour, ponderal growth and level of parasitic infestation were studied in Suffolk breed sheep, from 1994 to 1995, in Nova Odessa, São Paulo. Two management systems were compared: restricted grazing, where the animals were released to the pastures at 9:50am and confined at 5:30pm, and 24 hour grazing, where the animals were maintained all the time in the paddocks, but with access to shelters. Thirty-four adult ewes were used in the summer period (17 under restricted grazing and 17 full-time grazing), and 42 ewes in the winter period (21 with restricted grazing and 21 full-time grazing). Also, for both seasons, 12 traceranimals, six in each grazing system, were used to obtain worm counts from their digestive tracts. For three consecutive days, grazing behaviour, that is, whether grazing or not, was observed in January/February (summer) and July/August (winter) at 30 minute intervals from 7:00am to 5:30pm, also whether the animals stayed in the sun or shade, irrespective of whether they were grazing or not. The level of parasitic infestation was evaluated under each system by eggs per gram countings (EPG) of the herd and the traceranimals, as well as by larvae count. It was concluded that restriction of grazing time by itself does not provide any effective control of parasitic infestation in sheep, however a better control was obtained in the summer period. Restricted grazing time was compensated by the greater activity of the animals during the hotter hours of the day, however, this behaviour affected the animal performance, resulting in lower weight gains. Greater forage availability in relation to estimated consumption may explain the similarity between the grazing times observed in both management systems, either in the summer or in the winter.

• Sheep Suffolk grazing behaviour management parasitic infestation

Abstract in Portuguese:

Foi estudado o comportamento em pastejo, o desempenho ponderal e o nível de infestação parasitária em ovelhas da raça Suffolk, no período de 1994 a 1995, em Nova Odessa, SP. Comparou-se dois sistemas de manejo: pastejo restrito, onde os animais foram soltos às 9:50h e presos às 17:30h e pastejo em período integral, no qual os animais não eram recolhidos, tendo a disposição abrigo para passarem a noite. Foram utilizadas 34 fêmeas adultas no verão (17 em pastejo livre e 17 em pastejo restrito) e 42 fêmeas adultas no inverno (21 em pastejo livre e 21 em pastejo restrito). Trabalhou-se ainda com 12 animais traçadores em cada estação do ano, sendo metade em cada sistema de manejo visando a contagem de nematódeos no trato digestivo dos animais. Durante 3 dias consecutivos nos meses de janeiro/fevereiro (verão) e julho/agosto (inverno) estudou-se, através da observação dos animais, a cada 30 minutos entre as 7:00 e 17:30h, o hábito de pastejo (pastando ou não; na sombra ou no sol). Acompanhou-se o nível de infestação parasitária dos animais em cada sistema, pela contagem do OPG do rebanho e dos traçadores e nematódeos recuperados nos traçadores. Concluiu-se que a restrição do horário de pastejo isoladamente não propiciou um controle efetivo da infestação parasitária nos animais mostrando. A restrição do tempo de pastejo é compensada pela maior atividade dos animais nas horas mais quentes do dia, todavia este comportamento afetou o desempenho, resultando em menor ganho de peso. A maior disponibilidade de forragem, em relação ao consumo estimado, pode explicar a similaridade entre os tempos de pastejo verificados nos dois sistemas de manejo, tanto no verão como no inverno.

• Ovinos Suffolk hábito de pastejo sistema de manejo infestação parasitária